AS207604 - UNITED United InternetRFC 4890 ✓RPKI ✓ 1/1ASPA -

AS overview

Test target: 2a0c:bf80:5a::1 · static prefix probe · address space: unknown · prefixes announced: 1

prefix(es): 2a0c:bf80:5a::/48

SOX peering

Random-IP probe (yarrp) into the AS' prefixes

We probed 35 arbitrary IPv6 address(es) inside AS207604's announced prefix(es). No router inside the prefix responded. The deepest visible hop was 2001:7f8:1e:8::34 at hop 10 - that router answers ICMPv6 Echo. This is not in AS207604's announced prefix; operationally it's the AS-edge / peering interface (often on a SOX peering address or an upstream's /127 link). The traceroute boundary is the AS edge: ICMPv6 Time-Exceeded responses from anything inside this AS are filtered.

ICMPv6 Type 2 (Packet Too Big) acceptance - active test

Type 2 honored. Forged ICMPv6 PTB (MTU=1280) was accepted by the destination's stack: the next 1500-byte Echo Reply arrived split into 2 fragments via the IPv6 Fragment Header.
method: ICMPv6 Echo + forged PTB, tested 2026-09-23T11:09:06Z

Multi-vantage path map

Every hop of all vantages’ traceroutes toward the target, drawn left→right, grouped into per-AS bubbles (a hop seen from several vantages is one shared bubble, so converging paths merge). It answers two questions per vantage — shown on each source bubble as echo ✓/⚠/✗ · trace ✓/✗: did the destination reply to ICMPv6 Echo (✓ honored, ⚠ replied but PTB not honored, ✗ no reply), and did the traceroute reach it. A line to the target is drawn only when that vantage got an echo reply — solid if the PTB was honored, dashed if not (reachable but a broken-PMTUD / RFC 4890 violation). The path depth still shows how far the traceroute itself got, and runs of unanswered (* *) hops collapse into one dashed “silent” bubble. Open full size ↗

• ● SRB host (SOX, Belgrade)
• ● DE host (Berlin)
• ● DE host (Düsseldorf)
• ● NL host (go6lab)
• ● ITA host (Karsolink)
• ● SLO host (6connect)
• ● SLO host (T-2)
• ── solid line = echo reply, PTB honored (clean reach)
• — — dashed line = echo reply but PTB not honored (RFC 4890 violation)
• no line = no echo reply (never reached)
• ◉ target: green = clean, amber = reachable-but-violation / unreachable
• ⚠ suspected drop AS
• ⋯ silent (unanswered) hops
• ● IXP hop

From SRB host (SOX, Belgrade)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.010ms pmtu 1500
 1:  _gateway                                              0.700ms 
 1:  _gateway                                              1.393ms 
 2:  united-internet.sox.rs                                0.779ms 
 3:  2a0c:bf80:5a::3                                       0.795ms reached
     Resume: pmtu 1500 hops 3 back 2 

From DE host (Berlin)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.022ms pmtu 1500
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                 15.146ms 
 1:  xe-0-0-13-178.gw01.ber01.as59645.net                  0.304ms 
 2:  ae0-2453.cr10.ber01.lwlcom.net                        0.892ms 
 3:  retn.bcix.de                                         10.673ms asymm  5 
 4:  RT.TNR.BEG.RS.retn.net                               28.602ms asymm  5 
 5:  GW-NETOPS.retn.net                                   35.043ms asymm  8 
 6:  GW-NETOPS.retn.net                                   29.510ms reached
     Resume: pmtu 1500 hops 6 back 8 

From DE host (Düsseldorf)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.022ms pmtu 1500
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.393ms 
 1:  xe-0-0-12-142.gw01.dus01.as59645.net                  0.273ms 
 2:  eth1-0-12-h5594.edge5-dus1.bb.wiit.network            1.248ms 
 3:  no reply
 4:  lag11.core3-dus1.bb.wiit.network                      0.386ms 
 5:  lag2.core1-dus-ix.bb.wiit.network                     0.465ms 
 6:  de-cix1.rt.act.fkt.de.retn.net                        4.632ms asymm  4 
 7:  RT.TNR.BEG.RS.retn.net                               23.011ms asymm  4 
 8:  GW-NETOPS.retn.net                                   23.651ms reached
     Resume: pmtu 1500 hops 8 back 7 

From NL host (go6lab)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.036ms pmtu 1500
 1:  2a00:8642:42::2                                       3.944ms 
 1:  2a00:8642:42::2                                       2.655ms 
 2:  gw.friends.steffann.nl                                5.604ms 
 3:  2a00:1ca8:1::194                                      5.348ms 
 4:  2a03:3f40::10:33                                      9.365ms 
 5:  ams-ix.retn.net                                       7.945ms asymm  7 
 6:  RT.TNR.BEG.RS.retn.net                               33.314ms 
 7:  GW-NETOPS.retn.net                                   41.950ms reached
     Resume: pmtu 1500 hops 7 back 6 

From ITA host (Karsolink)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

Rate-limited ICMPv6: hop 5 (loss between 5% and 95% across mtr cycles - the router replies but only sometimes).

tracepath -6

 1?: [LOCALHOST]                        0.047ms pmtu 1500
 1:  karsolink-01.net.karsolink.com                        0.442ms 
 2:  2a12:d8c0:109f:121::a1                                0.551ms 
 3:  2a12:d8c0:101f:6::1                                  67.195ms 
 4:  no reply
 5:  100ge0-0-0-20.core1.vie1.he.net                      22.439ms 
 6:  e0-35.core2.bts1.he.net                              21.620ms 
 7:  e0-36.core2.beg1.he.net                              29.193ms 
 8:  serbian-open-exchange-doo.10gigabitethernet1-1-2.switch1.beg1.he.net  26.872ms asymm  7 
 9:  united.sox.rs                                        27.269ms asymm  7 
10:  2a0c:bf80:5a::3                                      27.030ms reached
     Resume: pmtu 1500 hops 10 back 7 

From SLO host (6connect)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.019ms pmtu 9000
 1:  fw1-lju.6connect.com                                  0.677ms 
 1:  fw1-lju.6connect.com                                  0.703ms 
 2:  ccr-to-fw-ccr1-gw-lju.6connect.com                    1.060ms 
 3:  2a00:ee1:800:9::1                                     2.123ms 
 4:  2a00:ee0:1:15::2                                      1.507ms asymm  3 
 5:  2a00:ee0:1:10::2                                      1.569ms pmtu 1500
 5:  de-cix1.rt.act.fkt.de.retn.net                       14.305ms asymm  9 
 6:  RT.TNR.BEG.RS.retn.net                               22.567ms asymm  8 
 7:  GW-NETOPS.retn.net                                   22.568ms reached
     Resume: pmtu 1500 hops 7 back 8 

From SLO host (T-2)   openRFC 4890 ✓

filter likely at: (none) · min PMTU on path: 1500

Path (traceroute + mtr + PTR)

tracepath -6

 1?: [LOCALHOST]                        0.028ms pmtu 1500
 1:  2a01:261:313:b814::1                                  0.691ms 
 2:  2a01:260:1::225                                       2.858ms 
 3:  2a01-260-1-1--9c.core6.t-2.net                        2.371ms 
 4:  2a01-260-1-1--38.core6.t-2.net                        2.828ms asymm  3 
 5:  100ge0-0-0-31.core1.vie1.he.net                      12.992ms 
 6:  e0-35.core2.bts1.he.net                              11.473ms 
 7:  e0-36.core2.beg1.he.net                              18.611ms 
 8:  serbian-open-exchange-doo.10gigabitethernet1-1-2.switch1.beg1.he.net  32.205ms asymm  7 
 9:  united.sox.rs                                        18.638ms asymm  8 
10:  2a0c:bf80:5a::3                                      18.679ms reached
     Resume: pmtu 1500 hops 10 back 8